Nearly every modern contract (JCT, NEC, bespoke) has an extension-of-time mechanism. That's the safety valve that stops employer-caused or neutral delay turning into LDs against you, and it's also how the client keeps the programme "contractual" instead of time going at large.
Your job is simple in theory: spot delay events, notify them on time, and prove how they push the completion date. The detail is where people mess it up.
1. The basic idea across JCT and NEC
Under both JCT and NEC-style contracts, not all delay is equal:
- Some events give you time but no money (EOT only).
- Some give you time and money (EOT + loss/expense or compensation event).
- Some are your own fault -- you get no time, no money, and you risk LDs.
The EOT system is there to:
- move the completion date when delay is due to specified relevant events (JCT) or compensation events (NEC) or similar;
- keep LDs enforceable only for your delay, not theirs.
Everything hangs off you using the notice and evidence rules properly.
2. JCT: how EOTs are meant to work
Under JCT (SBC/DB/IC etc.), the contract administrator (or employer's agent) can adjust the completion date when certain "Relevant Events" delay the works.
In broad strokes:
-
Relevant Events include things like: instructed variations, deferment of possession, exceptionally adverse weather, strikes, force majeure, specified perils, some statutory changes, and sometimes other client-side or neutral events depending on the edition/amendments.
-
The contractor must give notice of delay "as soon as it becomes reasonably apparent" that progress is or is likely to be delayed by a Relevant Event.
-
That notice should identify the event, its expected effect on completion, and is usually followed by more detailed particulars/updates.
-
The CA must then assess and decide the EOT, and notify the adjusted completion date, typically within a set period (e.g. 8 weeks from getting sufficient info in newer JCT forms).
Under modern JCT, the days when an architect could quietly "do justice" even if you didn't notify are largely gone. Courts and commentary now treat notice and particularisation as important -- miss them, and you're on thin ice.
3. NEC: early warnings, compensation events and time bars
NEC doesn't talk about "EOT" in the JCT sense. It deals with time (and money) through compensation events, backed by early warnings and strict time bars.
Key bits:
-
Early warning (Clause 15) -- you must notify as soon as you're aware of any matter that could delay completion or increase price, not just events that already have.
-
Compensation events (CEs) -- listed events (scope changes, late instructions, unexpected physical conditions, weather, others) that entitle you to extra time and/or money.
-
Eight-week time bar (Clause 61.3) -- in NEC4 ECC, if you don't notify a CE within 8 weeks of becoming aware of it, the prices and Completion Date are not changed, unless it arises from a PM/Supervisor instruction/certificate/changed decision.
So under NEC:
- Early warnings protect the project and your credibility.
- CE notices protect your time and money -- miss them, and you lose entitlement, full stop.
That's why NEC people keep repeating "no notice, no money, no time".
4. How to actually claim an extension properly (whatever the form)
Strip the labels off, and a solid EOT/CE claim has four moving parts: event, entitlement, impact, mitigation.
Spot and notify the event early
- The clock starts when it becomes reasonably apparent (JCT) or when you are "aware" (NEC) that an event may delay completion.
- Don't wait until the delay has fully hit; by then, your notice window may be closing.
Your notice should:
- be in writing, dated, and headed clearly (e.g. "Notice of Delay / Notice of Compensation Event");
- identify the contract clause / Relevant Event / CE you rely on;
- briefly describe what happened and why it's likely to delay completion.
Explain the cause and effect
Follow up with particulars that:
- set out the sequence of events (timeline);
- show which tasks in the programme are hit and for how long;
- distinguish between compensable delay (theirs) and non-compensable (yours).
This is where updated programmes, delay analyses and site records matter -- even if it's simple logic rather than a full forensic analysis on smaller jobs.
Show you mitigated
Courts and contract admins expect you to have tried to reduce delay:
- re-sequencing, adding resources, working around issues where reasonable.
- document what you did -- this strengthens both your EOT entitlement and any money claim.
Track the decision and push if it stalls
- Under JCT, the CA has set periods to issue an EOT decision; under NEC, the PM has tight timescales around CEs and programme acceptance.
- If they don't decide, you don't just shrug -- you escalate, and, if needed, set yourself up for adjudication to crystallise rights before LDs are deducted.
All of this is easier if you've built the habit of regularly updating your programme and keeping half-decent site diaries, rather than trying to reconstruct delay a year later.
5. Practical habits that stop EOTs becoming a car crash
Non-negotiables:
-
Know your triggers -- at project start, mark up the contract's Relevant Events/CEs and notice time limits, and share that crib with site and commercial.
-
Separate early warning from CE/EOT notices (NEC) -- an early warning alone doesn't protect time/money; you still need the formal CE notification.
-
Use plain but precise language -- you don't need Latin, just clear facts tied to the right clause.
-
Update your programme when things move -- any serious EOT/CE claim will live or die on whether your programme looks like a real planning tool or a wallpaper chart.
-
Don't bank on "time at large" -- your first line of defence is always a properly notified, evidenced EOT/CE claim, not a Hail Mary argument that the whole time regime has collapsed.
Extension of time (EOT) / CE notice checklist
Before you hit send on a delay notice, check you've covered:
- Correct form and addressee: Sent to the person/body named in the contract (CA/PM/Employer) by the method the contract specifies (email/portal/post).
- Right heading and reference: Clearly labelled (e.g. "Notice of Delay -- Relevant Event [X]" or "Notice of Compensation Event under clause [Y]") with project and contract refs.
- Event identified and dated: What happened, when it started, and which clause/Relevant Event/CE you say it falls under.
- Impact explained in outline: Short explanation of how it is likely to delay completion (which activities, approx. duration), with a note that fuller particulars/programme update will follow.
- Mitigation noted: Briefly say what you've already done or will do to minimise delay (re-sequence, extra resources, work around), so it doesn't look like you're just waving the contract.
- Timing within the contract window: You're serving it "as soon as reasonably apparent" (JCT) or within any specified time bar (e.g. 8 weeks from awareness under NEC).
- Evidence ready to follow: You've got (or are pulling together) programmes, diaries, emails and photos to back up the claim when they ask for particulars.
If a notice hits all of that, you've done most of what the contract and any adjudicator will expect when you later argue about time and LDs.
Disclaimer: SiteKiln gives you plain-English information, not legal advice. Talk to a solicitor before making big decisions on live disputes.
What to do next
- At project start, mark up the contract's Relevant Events (JCT) or compensation events (NEC) and the notice time limits, and share that crib with site and commercial teams.
- When a delay event happens, serve a written notice immediately -- do not wait until the delay has fully hit.
- Follow up your initial notice with detailed particulars showing which programme activities are affected and for how long.
- Update your programme regularly so any EOT or CE claim is backed by a credible planning document, not wallpaper.
- If the contract administrator or project manager does not issue an EOT decision within the required time, escalate -- and if needed, set yourself up for adjudication before LDs are deducted.
Sources
- Housing Grants, Construction and Regeneration Act 1996 -- https://www.legislation.gov.uk/ukpga/1996/53/contents
- Scheme for Construction Contracts (England and Wales) Regulations 1998 -- https://www.legislation.gov.uk/uksi/1998/649/contents
Know someone who needs this?
Was this guide useful?
Didn't find what you were looking for?
Spotted something wrong or out of date? Email us at hello@kilnguides.co.uk.
In crisis? Samaritans 116 123 ·